Getting Started

1. Download Signal

2. Subscribe to the Signalboost Announcements and Helpline channel

Send HELLO to +1-947-800-5717 (that's 947-BOOST-IT!)

Send INFO to see details about the channel.

Send HELP to see the other commands you can use.

3. Request your own channel:

Send a Signal message to +1-947-800-5717 that includes channel name and the phone numbers of at least 2 admins. For example:

Test Channel +1-123-555-5555, +1-123-555-5555

You will receive a welcome message from your new channel phone number as soon as your channel is created.

You can write our helpline with questions or a request for a more in-depth training, and we'll get back to you asap!

4. Get subscribers and send announcements

Now, any anyone who sends "HELLO" to your channel number will get announcements you send out!

Signalboost Guide

A Signalboost channel is a phone number that keeps track of admins and subscribers. Any time an admin sends a message to the channel, it is interpreted as a command or a broadcast. If admins send a broadcast, all of the subscribers will see it, but Signalboost will route the broadcast so that it appears as if coming from the channel phone number.

People have described Signalboost as "BCC, but for messaging," "secure SMS blasts," and "Celly, but over Signal."

Commands & languages

A command is a word or phrase sent as a Signal message that Signalboost will interpret as an instruction. Some commands can only be used by admins. If you're unsure which command to use, the HELP command is a great place to start.

Signalboost currently supports English, Spanish, French, and German. To switch to your language of choice, type the name of the language into the channel. For example, if I want to switch my language to Spanish, I would send "ESPAÑOL" to the channel.

Disappearing Messages

By default, messages on Signalboost channels disappear after 1 week. However, admins and admins only can override the 1-week duration using the disappearing message timer in the top right hand corner of the Signal app. We recommend shortening the duration of disappearing message timer (usually to 1 day or 6 hours) if your broadcasts will contain sensitive information.


How do I get people to join my channel?

Here's a short video of how to get people to subscribe to updates from your channel. They can send HELLO to your channel phone number or you can invite them.

How do I broadcast a message?

If you're an admin, use the BROADCAST command or the ! shortcut to broadcast a message to all the members of a channel:

BROADCAST Hello everyone! Community Meeting at 6pm this evening.
! Hello everyone! Community Meeting at 6pm this evening.

Here's a short video of what that looks like.

How do I respond to a hotline message?

Incoming hotline messages are followed by an @id:

[HOTLINE @3214]
Hello! We need a legal representative at jail support location XYZ.

In order to respond privately to that person, type @ followed by the id:

@3214 Okay, we are sending someone over!

And the subscriber you replied to will receive the following message:

Okay, we are sending someone over!

How can I see a list of commands I can use?

HELP lists the possible commands you can use.

How can I see my channel name, description, and how many people are subscribed?

INFO shows stats and briefly explains how Signalboost works.

Managing your channel

ADD / REMOVE +1-555-555-5555

Adds or removes +1-555-555-5555 as an admin of the channel. Any admins can remove or add any other admins.

RENAME new name

Renames channel to "new name"

RENAME My Cool Signalboost Channel

DESCRIPTION description of channel

Adds or updates public description of channel.

DESCRIPTION This is the _super cool activist_ signalboost channel! We'll use it to make announcements for the upcoming protest.


VOUCHING ON: turning vouching on means that an invite (1 by default) is required to join the channel. Both admins and subscribers can invite people to the channel using the INVITE command.

VOUCHING OFF: this is the default behavior of the channel; anyone can join by sending HELLO to the channel number.

VOUCHING ADMIN: this means that an invite from an *admin* is required to join the channel. If other people try to send invites, they will be prevented from doing so.

INVITE +1-555-555-5555

Invites +1-555-555-5555 to subscribe to the channel. Remember to preface the phone number with a + and country code!

Multiple invites can be sent by listing phone numbers separated by commas:

INVITE +1-555-555-5555, +1-333-333-3333


This changes the number of invites needed to join the channel. For example:


After executing this command, anyone who wants to join the channel will need 3 invites.

Managing a hotline


Enables or disables a hotline, which allows admins to receive anonymous messages from subscribers. Channel hotlines are off by default. If you're an admin, you'll know that a message coming in is a hotline message because it will have the following header:

[HOTLINE #3214]

If you decide to turn the hotline on:

  • Your subscribers' anonymity will be preserved when they message the hotline.
  • Depending on the number of people subscribed to your channel, the hotline can be noisy and increase the chances of spam/abuse.

Other useful commands

PRIVATE good morning fellow admins!

Sends a private message to admins only (subscribers will not be able to see those messages).


Switches language to Spanish, French, or German. Language changes on Signalboost are user-specific, so if you change your language to Spanish other admins and subscribers' channels will be unaffected.


Leaves the channel. If you're an admin, you will lose your admin access to the channel but will still be able to subscribe as a subscriber. If you want to obtain admin access again, you will need to ask a current admin to add you using the ADD command.


Danger zone! This command permanently destroys the channel and all associated records. Importantly, it does not erase the message history from admin and subscribers phones until the duration of the disappearing message timer is up.